Body size is a key determinant in individual health. While a person’s weight was once the key measurement in healthy weight management, experts now recommend using body fat. Body fat can be measured in many different ways. The most common body fat testers are body mass index (BMI), calipers, electronic body fat analyzers, and water displacement.
The easiest way to estimate body fat percentage is through the use of a BMI calculator. BMI calculators take the height and weight of a person and use it to calculate the amount of body fat. There are a variety of free BMI calculators available online. The formula for calculating BMI using metric measurements is weight in kilograms divided by height in meters squared (kg/m²). To calculate BMI using imperial measurements, the formula is weight in pounds multiplied by 703 divided by height in inches squared (lb X 703/in²).
Inexpensive body fat testers called calipers are available at most fitness and many other retail outlets. Calipers are used to pinch the skin and underlying body fat at certain key points on the body. Once the measurements have been taken, they are added together to determine the overall body fat level. Digital calipers are similar to manual calipers, but they simplify the process by taking care of the calculations. Many fitness centers use calipers or digital calipers to determine body fat percentage.
Electronic body fat testers, also called portable body fat analyzers, are considered by many to be more accurate than calipers. The device is shaped like a video game controller and is held in both hands with the arms extended out from the body. The computer then analyzes the body fat percentage and displays it on the screen. Like calipers, electronic body fat testers are commonly available from retail stores.
Water displacement is considered to be the most accurate of the body fat testers. Also called hydrostatic testing, this method is based on the principle that lean mass, made up of bone, muscle, and connective tissue, sinks in water while body fat floats. To conduct water displacement testing, a person is submerged in water on an underwater scale and then blows all of the air from her lungs. This method can be uncomfortable and intimidating as well as expensive.
Healthy body fat levels vary based on age and gender. A certain amount of body fat is necessary for normal body functions, such as temperature control and organ insulation. Unusually high levels of body fat are a sign of obesity and can lead to a variety of health related issues.